Accelerating the Crystallization of Zeolite SSZ-13 with Polyamines.

Tailoring processes of nucleation and growth to achieve desired material properties is a pervasive challenge in synthetic crystallization. In systems where crystals form via nonclassical pathways, engineering materials often requires the controlled assembly and structural evolution of colloidal precursors. In this study, we examine zeolite SSZ-13 crystallization and show that several polyquaternary amines function as efficient accelerants of nucleation, and, in selected cases, tune crystal size by orders of magnitude. Among the additives tested, polydiallyldimethylammonium (PDDA) was found to have the most pronounced impact on the kinetics of SSZ-13 formation, leading to a 4-fold reduction in crystallization time. Our findings also reveal that enhanced nucleation occurs at an optimal PDDA concentration where a combination of light-scattering techniques demonstrate these conditions lead to polymer-induced aggregation of amorphous precursors and the promotion of (alumino)silicate precipitation from the growth solution. Here, we show that relatively low concentrations of polymer additives can be used in unique ways to dramatically enhance SSZ-13 crystallization rates, thereby improving the overall efficiency of zeolite synthesis.

Sodium houttuynia alleviates airway inflammation in asthmatic mice by regulating FoxP3/RORγT expression and reversing Treg/Th17 cell imbalance.

Synthetized from a natural oil of Houttuynia cordata, sodium houttuynia was reported to have anti-inflammatory effects. The present study aimed to investigate whether sodium houttuynia could alleviate the characteristic airway inflammation and Treg/Th17 cell imbalance of asthma in vivo. Experimental mice with neutrophilic asthma were injected with sodium houttuynia or dexamethasone (alone or in combination) intraperitoneally. The airway reactivity was measured, and bronchoalveolar lavage fluid was collected for cell count. Hematoxylin/eosin and periodic acid-Schiff staining were performed to assess pulmonary inflammation and mucus hypersecretion. Immunohistochemical analysis was conducted to determine the expression of IL-10, IL-17A, FoxP3, and RORγT in the lung tissue, and the serum levels of IL-10 and IL-17A were analyzed by ELISA. The proportion of CD4+CD25+FoxP3+ Treg and Th17 cells within the CD4+ T cell subset of splenocytes was analyzed by flow cytometry. FoxP3 and RORγT mRNA and protein expressions in the lung were analyzed by real-time PCR and western blot, respectively. Overall, sodium houttuynia was found to ameliorate the Treg/Th17 cell imbalance and reduce the airway inflammation, hyperresponsiveness, and mucus hypersecretion by increasing the frequency of CD4+CD25+FoxP3+ Treg cells and the secretion of IL-10, while decreasing the proportion of Th17 cells and IL-17A production. Although the regulatory effect of sodium houttuynia was not as good as that achieved with dexamethasone, combination of the two compounds showed improved inhibitory effects on airway hyperresponsiveness, inflammation, and mucus hypersecretion. Hence, sodium houttuynia may be beneficial for the treatment of asthma.